#12 Handle partial DVI files

[Stefan Ulrich]

Make it possible to read partial DVI files, i.e.
without depending on the presence of a postamble.

This would make it possible to do `incremental' display
of a DVI file while it is compiled.

It requires that font setup doesn't depend on the
postamble, as it currently does (`read_postamble' in
dvi-draw.c). It would also allow for PK creation
on-demand (or in batch, while xdvi waits for events)
instead of at startup as it is now (even though this
point has become less urgent with t1lib).

[Stefan Ulrich]

Logged In: YES
user_id=177175

(FWIW, the use of a backup file in xdvik-22.76-RC1 has made
this request somewhat less pressing).